Avalanche forecast

Stevens Pass

Northwest Avalanche Center
View on map

Avalanche danger

Mon
Alpine
4 · High
Treeline
4 · High
Below
4 · High
Open full map
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Heavy snow, strong winds, and warming temperatures will create very dangerous avalanche conditions on Sunday. Avalanches will run at all elevations and could be very deep and destructive. Avoid going into, near or underneath anywhere an avalanche could start, run and stop through Monday while a significant avalanche cycle is underway. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    A foot or more of new snow will fall, and temperatures will rise significantly first thing in the morning on Sunday. Storm slabs may become easily triggered and could run naturally. These won't' be your light and fluffy kind, they will be thick and dense. Very strong winds will blow, creating thicker and more reactive slabs in any exposed, open slopes. You could trigger storm slabs from distance, and they could step down to become unsurvivable deep slab avalanches. Stay off of, and out from underneath avalanche terrain.

    Example storm slab avalanche.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2

    Rain on snow, or wet snow on dry snow will cause wet loose avalanches. These could grow to become large on steep slopes. Wet slab avalanches aren't out of the question either, and become very large and destructive. Wet slides could run over common hiking trails and snowmobile trails in the zone. Stay off of, and out from underneath any steep slopes on Sunday, even at low elevations.

    Example large, wet loose avalanche.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    3

    The deep slab appears to be waking up. On Saturday afternoon a very large avalanche was spotted west of Skyline in steep SW facing terrain. Warming temperatures and heavy snowfall may overload this layer in a more widespread way on Sunday through Monday. As evidenced by this recent slide, and propagation tests at 4,000ft, deep slabs can occur even well below treeline. Avalanches could run into mature timber and become very destructive. Stay off of, and well out from underneath any steep open terrain at any elevation on Sunday through Monday.  

    (2/20/2021) This very large deep slab avalanche occurred in the afternoon on Saturday. It appeared to be triggered by a skier but details are unknown. Crown estimated at 4-5' deep.

Avalanche Discussion

An atmospheric river looks to bring warming temperatures, very strong wind, and heavy rain/snow to the area. 73 inches of snow has fallen at the Brooks weather station on Steven’s Pass since February 12, and much more is on the way, but this time in the form of heavy, dense snow. We haven't seen rain above 3,500ft or so since mid-January, so one of the main concerns is that slabs 5-10' feet thick may begin to come crashing down starting on Sunday. The avalanche cycle may last through the day Monday. Saturday's deep slab avalanche may be a precursor to more very large avalanches. In any case, large storm slabs and wet loose avalanches are expected to run from steep slopes on Sunday as our once beautiful cold, dry snow becomes overloaded by wet, heavy rain and snow. This is not your average High avalanche danger, and we may reach Extreme danger by the end of Sunday. Stay off of, and out from underneath avalanche terrain. Be careful of roof avalanches on Sunday, snow will begin sliding off buildings with the warmup.

Back on the 16th, a widespread storm slab avalanche cycle occurred, ranging in size from D1-D2.5. One of these was a deep and very wide avalanche on the South Face of Mount McCausland (See photo below). WSDOT avalanche workers triggered multiple large and a couple of very large avalanches during control work early Tuesday morning. On Monday, an observer reported natural avalanches on steep southerly aspects below Skyline Lake. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regions covered